Investigation of Anomaly maps of groundwater quality parameters(Case study: Jiroft watershed)

Awareness of spatial variations of qualitative parameters is an important tool in order to understand the capabilities of the region and how to manage the lands. Through the current study, the spatial and temporal changes of EC, SAR, TDS and TH parameters were analyzed using geostatistical methods during the two statistical periods of 2004 and 2014 in groundwater's. For this purpose, the data related to the analysis of 44 water wells in Jiroft plain, where has a middle hot desert climate were obtained according to the latest sampling in 2014. The Geostatistical methods used to zone the mentioned parameters include ordinary kriging and inverse distance weighing (IDW) with different powers. In order to evaluate the geostatistical pitch methods, the mutual evaluation technique used applying the RMSE, MBE, MAE and R2 criteria between actual and estimated data. The results of the ranking of evaluation criteria showed that for the EC and TDS parameters, the Kriging method with a spherical model, and for the SAR and TH, the method of inverse distance to the power of 2 and 3 respectively, has the least error. The performed studies show that the spatial correlation of the qualitative parameters mentioned in the Jiroft Plain is very high. The error of the semi-variogram model of the measured sodium absorption ratio during the statistical period of 2004-2005 with a nugget effect of 0.97 and a range of effect, 23 km, is equal to 14.2%, and the error of the semi-variogram model during the statistical period of 2014-2015 with a nugget effect of 0.23 and a range of effect, 28 km, is equal to 14.2%. The results of the anomaly maps of the qualitative parameters in Jiroft plain indicated that the most of the changes are in the eastern part (Jebalbarez District) and northwest (Sarduiyeh District) and the least of the changes are in the southern parts of the plain